Variation characteristics of climatic potential yield and resources utilization efficiency of maize under the background of climate change in agro-pastoral transitional zone of Gansu, China.

To evaluate the effects of changes in radiation, accumulative temperature, precipitation and climate resources on climate resource utilization efficiency in the agro-pastoral transitional zone of Gansu Province, we analyzed the variations of climate potential yield loss rate, light, heat, precipitation and comprehensive utilization efficiency of climate resources in the agro-pastoral transitional zone of Gansu Province by the step-by-step correction and indexation method, with the 1971-2020 weather data from 45 meteorological sites and the maize phenology data. The results showed that solar radiation showed fluctuating downward trend at a rate of -22.03 MJ·m-2·(10 a)-1, the accumulative ≥11 ℃ temperature showed significant upward trend at a rate of 60.89 ℃·(10 a)-1, the precipitation showed slow upward trend at a rate of 2.05 mm·(10 a)-1 during the study period. The climate potential yield loss rate due to temperature and precipitation limitations was relatively high in Gannan and the northern part of Longzhong, while it was relatively low in the most areas of Longdong. Except for the central part of the study area and part of Longdong, the climate potential yield loss rate due to temperature and precipitation limitations in other regions of the study area showed decreased trend at the rate of -2.0%·(10 a)-1 and -0.6%·(10 a)-1. The low-value areas of light and heat utilization efficiency distributed in the northern and southern parts of Longzhong and part of Gannan, the low-value area of precipitation utilization efficiency distributed in Gannan, and the low value of comprehensive utilization efficiency distributed in Lanzhou and Baiyin which were 0.41 and 0.47, respectively. Longdong was the most suitable for maize planting, where the climate resources utilization efficiency of maize was highest, followed by Gannan and Longzhong. The average tendency rate of light, heat, precipitation and climate resources comprehensive utilization efficiency in the study area showed increased trend, which were 0.1%·(10 a)-1, 0.07 kg·hm-2·â„ƒ-1·d-1·(10 a)-1, 1.17 kg·hm-2·mm-1·(10 a)-1 and 0.05 ·(10 a)-1, respectively, showing a good potential to increase maize yield.

Evaluating the effects of different sowing dates and tillage methods on dry-land wheat grain dry matter accumulation based on the APSIM model.

Accurate simulation of dry matter accumulation in wheat grains can provide important technical support for regulating wheat production in hilly areas of Loess Plateau. Using the APSIM model, we analyzed dryland wheat grain dry matter accumulation and distribution using the meteorological data from 1971 to 2017 in Anding District, and the field test data from 2016 to 2017 in Anjiagou Village, Fengxiang Town, Anding District, Dingxi City, Gansu Province. Furthermore, the influence of sowing date and tillage method on dry matter accumulation of wheat grain was quantitatively analyzed on the basis of model validation. The results showed that the root mean square error (RMSE) between the simulated and measured values of grain dry matter was 57.5-143.1 kg·hm-2 and the normalized root mean square error (NRMSE) was 1.4%-9.9% under the three sowing dates and four tillage methods, respectively. The precision of the APSIM model was satisfactory. Under different sowing dates, the order for beneficial degree of tillage treatment to dry matter accumulation in wheat grains was no tillage with straw cover > conventional tillage with straw cover > no tillage > conventional tillage. The treatment of no tillage with straw covered was the most favora-ble to dry matter accumulation in wheat grains, with no significant difference between no tillage and conventional tillage treatments. Under different farming methods, early sowing was better than normal sowing and late sowing for the dry matter accumulation process of wheat. Late sowing had stronger impacts on dry matter accumulation, with the least ideal accumulation process.

Decrease of GSK3ß Ser-9 Phosphorylation Induced Osteoblast Apoptosis in Rat Osteoarthritis Model.

Nowadays, the cumulative intake of glucocorticoids has become the most common pathogenic factor for non-traumatic osteonecrosis of the femoral head (ONFH). Apoptosis of osteoblasts is considered as the main reason of ONFH at the molecular level. Glycogen synthase kinase 3ß (GSK3ß) is an important regulator of cellular differentiation and apoptosis pathway, which can modulate the balance between osteoblasts and osteoclasts. Several studies have reported about its function in osteoporosis, but little is known about it in osteonecrosis. In our study, lipopolysaccharide and methylprednisolone were utilized to establish a rat ONFH model. The phosphorylation of GSK3ß Ser-9 was decreased in the model. Western blotting examination of ß-catenin, Bcl-2, Bax and caspase-3 revealed that the osteoblasts were apoptotic. In dexamethasone (Dex)-incubated primary osteoblasts, the expression profile of GSK3ß phosphorylation and apoptotic factors were consistent with those in the rat ONFH model. To further investigate the regulation of osteonecrosis caused by GSK3ß, the expression and function of GSK3ß were inhibited in Dex-incubated primary osteoblasts. The knockdown of GSK3ß by siRNA decreased the expression of Bax and cleaved caspase-3, but increased Bcl-2 and ß-catenin. On the other hand, selective inhibition of GSK3ß function by LiCl counteracted the activation of caspase-3 induced by Dex. Our work is the first study about the GSK3ß phosphorylation in ONFH, and provides evidence for further therapeutic methods.

Sesamin Protects the Femoral Head From Osteonecrosis by Inhibiting ROS-Induced Osteoblast Apoptosis in Rat Model.

Glucocorticoids intake has become the most common pathogenic factor for osteonecrosis of the femoral head (ONFH). Annually, tens of millions of patients suffer from pain related to ONFH. Researchers have proposed several underlying mechanisms of ONFH, including osteocyte apoptosis, cell differentiation disorder, and angiogenesis hindrance. Sesamin, isolated from Sesamum indicum seeds, was reported could affect osteocyte inflammation and differentiation in osteoarthritis and osteoporosis. We investigated the underlying influence of sesamin on ONFH rat model. Fifteen male Sprague-Dawley rats were randomly divided into three groups. The ONFH model group only received the methylprednisolone (MPS) and lipopolysaccharide (LPS) injection to promote the development of ONFH. The sesamin treatment group was injected with sesamin, MPS, and LPS. The control group was untreated. Rats from above groups were sacrificed 4 weeks later. The effect of sesamin on ONFH rats was validated by H&E staining. TUNEL staining showed that femoral head necrosis was attenuated by sesamin. Furthermore, the phosphorylation of Akt was increased and the downstream cellular apoptosis signal pathway was inhibited. Intracellular ROS level was decreased after sesamin treatment. In conclusion, our findings suggest that sesamin protects the femoral head from osteonecrosis by inhibiting ROS-induced osteoblast apoptosis.